An evaporator of, for example, a vapor-compression transport refrigeration system is generally positioned in a space to be cooled and allows heat exchange between refrigerant in the evaporator and air in the space during a cooling cycle. Liquid refrigerant coming out of a condenser usually goes through an expansion device, such as a thermostatic expansion valve (TXV), to turn into a vapor/liquid refrigerant mixture entering an inlet of the evaporator. The TXV can have a remote thermal control bulb positioned at the exit of the evaporator that can sense a temperature change of the superheat refrigerant vapor at the exit of the evaporator and control the volume of refrigerant entering the evaporator through the TXV accordingly. If the temperature of the superheat refrigerant vapor measured at the exit of the evaporator increases, the remote thermal control bulb can cause the TXV to open up so that more refrigerant may be permitted through the TXV. If the temperature of the superheat refrigerant vapor measured at the exit of the evaporator decreases, the remote thermal control bulb can cause the TXV to close down so that less refrigerant may be permitted through the TXV. The remote thermal control bulb can be configured so that the state of the refrigerant at a position where the bulb is attached is in a vapor state.